Door Assembly for Railcars

ABSTRACT

A door assembly for a railcar includes a sliding system and a latching system. The sliding system is operable to slide the door to a side of the entrance of the railcar to provide an opening path to an entrance of the railcar. The sliding system comprises one or more rollers used for sliding the door. The latching system is operable to plug the door to the railcar such that the door moves inward toward the railcar, and unplug the door from the railcar such that the door moves outward from the railcar. The latching system comprises a lever operably coupled with two or more gears. The lever turns a particular number of rotations in a first direction to plug the door to the railcar. The lever turns the particular number of rotations in a second direction to unplug the door from the railcar.

RELATED APPLICATION AND CLAIM TO PRIORITY

This application claims priority to U.S. Provisional Application No. 63/192,309 filed May 24, 2021 and titled “A DOOR ASSEMBLY FOR RAILCARS,” which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates generally to railcars and, more particularly, to a door assembly for railcars.

BACKGROUND

Railcars use several door types to provide access to the interior of the railcars. Generally, these doors are moved on guide rails to one side of the railcar opening to provide access to the interior of the railcar. Existing railcar door types comprise a sliding door and a plug door.

To open the sliding door, the sliding door is slid to a side of the railcar opening by using rollers at the bottom of the sliding door. Closing the sliding door is the reverse of the opening operation. However, the sliding door type does not create a robust sealing surface between the railcar and the door when the door is closed. Furthermore, current sliding door designs cause vibrations and movements as the railcar travels, which causes damages to the sliding door and the railcar.

To open a plug door, the plug door is first moved outward to “unplug” the opening and then moved to one side on guide rails until clear of the railcar opening. To move the door outward, a lever on the exterior side of the plug door is rotated, which causes the plug door to move outward. Once the plug door is moved outward a sufficient distance to clear the side of the railcar, the plug door may be moved to one side to reveal the railcar interior through which rail cargo may be loaded or unloaded. The plug door is typically pushed to the side either by hand or by mechanical means, such as a forklift. To close the plug door, the door is moved inward (i.e., toward the centerline of the railcar) that causes the door to “plug” the railcar opening. However, the plug door type does not provide a robust latching mechanism when the door is closed.

Furthermore, railcar doors are designed to be operated manually. Once unlatched, the door can be rolled open. However, in practice, sometimes the doors are opened and closed using the forklift forks, potentially damaging the door in the process. If an operator has to both open the door and drive the forklift into the railcar, either the operator has to dismount the forklift to open the door and then remount the forklift to drive it, or use the forklift to open the door and then begin the loading/unloading process. Dismounting and remounting the forklift while loading/unloading process not only takes more time but can lead to other unpleasant ergonomic situations.

SUMMARY

To address the foregoing problems, systems and methods are disclosed herein for providing a door assembly for railcars. The present disclosure provides a solution to improve the current railcar door design technologies. The disclosed systems and methods can be applied to vans, box trucks, over-the-road trailers, shipping containers, etc.

Several embodiments are elaborated in this disclosure. In accordance with a particular embodiment, a door assembly for a railcar is disclosed. The door assembly includes a sliding system and a latching system. The sliding system is operable to slide a door to at least one side of the railcar to provide an opening path to an entrance of the railcar when the door is opened. The sliding system comprises one or more rollers used for sliding the door. The latching system is operable to plug the door to the railcar such that the door moves inward toward the railcar. The latching system is further operable to unplug the door from the railcar such that the door moves outward from the railcar. The latching system includes a first gear with a first radius. The latching system further includes a second gear with a second radius, where the second gear is operably coupled with the first gear. The latching system further includes a lever operably coupled with the first gear and the second gear. The lever is operable to turn a particular number of rotations in a first direction to plug the door to the railcar. The lever is further operable to turn the particular number of rotations in a second direction to unplug the door from the railcar. The ratio of the first radius over the second radius is determined such that the lever is operable to turn when a force within a target force range is applied to turn the lever the particular number of rotations.

Various embodiments presented herein provide several technical solutions and practical applications to technical problems described above, which include providing a door assembly that improves the latching system, locking system, sealing system, and interface system for the railcar.

As an example, the disclosed system provides a technical solution of providing an improved latching system. In one embodiment, the disclosed latching system comprises a lever operably coupled with a gear system. The gear system is connected to locking rods. The locking rods comprise cams at the top and bottom ends. The cams are configured to rotate and engage with their corresponding keepers mounted on the railcar. When the lever is rotated, the gear system rotates, which causes the locking rods and the cams to rotate around their vertical axis. As the cams rotate, they engage their corresponding keepers, which causes the door to latch or plug to the railcar. The gear system comprises gears that are designed such that when a lever of the door is turned a particular number of rotations, the door is latched or unlatched (or plugged or unplugged) from the railcar. The gear system is designed to allow for a fewer rotations of the lever to operate the door compared to the current railcar door designs. As such, each of the processes of latching and unlatching the door requires less time and force.

As another example, the disclosed system provides an additional technical solution of providing an improved sealing system. In one embodiment, the disclosed sealing system comprises a plurality of sealing components that is attached to the surrounding surface on the outboard interior of the door. The plurality of the sealing components may be located on or near the outboard side of the structure around the door such that it allows for extra clearance to the interior space of the railcar compared to the current railcar door designs.

Furthermore, the disclosed sealing system provides an additional seal (i.e., bottom sealing surface) along the bottom of the door. The bottom sealing surface is located above the structure of the floor of the railcar. The bottom sealing surface is provided by a side sill portion that surrounds the structure of the door. This provides an additional practical advantage of installing the disclosed door assembly on modular railcars, shipping containers, over-the-road trailers, box trucks, vans, and the like. In modular railcar designs, the top portion of the railcar (e.g., the roof, doors, and the walls) can be separated from the bottom portion of the rail car (e.g., the floor), and be replaced with a new top portion. In some cases, the new top portion may not have a door opening. Therefore, if the side sill had a cut-out for the door, it would cause higher stress and pressure on the side sill than necessary. In current railcar door design technologies, the opening to the interior of the railcar is incorporated in the side sill. This makes it difficult (or impossible) to replace the top portion of the railcar with a new top portion. As such, in the disclosed system, the side sill is coupled to the door such that it allows installing the door assembly on modular railcars. The disclosed sealing system provides an easier opening and allows for watertight sealing.

The disclosed system may further allow for replacing a double-plug door with a single door to ease opening yet provide as much or more (or less as required) width to access the interior. The disclosed system may further allow for installing the door to be either insulated or remain uninsulated. This makes the disclosed system flexible to be used for uninsulated shipments and to be insulated for other types of shipments.

As another example, the disclosed system provides an additional technical solution of providing an improved interface system. In one embodiment, the disclosed interface system comprises one or more push pockets that are configured to interface with a device that is used for opening and closing the door, such as a forklift. The push pocket provides an opening space or “pocket” that is deep enough and wide enough to allow, for example, a blade of a forklift to fit in the pocket. The push pocket is also made with a material (e.g., steel) with a thickness to withstand significant impact or pressure from a forklift. In the current railcar door design technologies, during the opening and closing a door, there is a significant potential to damage the door. As such, the push pockets can be used to interface with a forklift to reduce (or eliminate) damages to the door.

Certain embodiments of the present disclosure may include some, all, or none of these advantages. These advantages and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

FIG. 1 illustrates a front view of an embodiment of a door assembly for railcars;

FIG. 2 illustrates an embodiment of a latching system for the door assembly of FIG. 1;

FIG. 3A illustrates an isometric view of an embodiment of a locking system for the door assembly of FIG. 1;

FIG. 3B illustrates a top view of an embodiment of the locking system for the door assembly of FIG. 1;

FIG. 4A illustrates a side view of a cross-section of the top of the door assembly of FIG. 1;

FIG. 4B illustrates a top view of a cross-section of a side of the door assembly of FIG. 1;

FIG. 4C illustrates a side view of a cross-section of the bottom of the door assembly of FIG. 1;

FIG. 5 illustrates a top view of a cross-section of a side of the door assembly of FIG. 1;

FIG. 6 illustrates a front view of an interface system for the door assembly of FIG. 1;

FIG. 7A illustrates a front view of an embodiment of a sliding system for the door assembly of FIG. 1; and

FIG. 7B illustrates a front view of an embodiment of a side sill portion for the door assembly of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary car 100 in a railcar 110. Examples of a railcar 110 include, but are not limited to, a box car, an auto rack car, a shipping railcar, an over-the-road box truck, a van, and a trailer. The railcar 110 comprises a door 120. The door 120 is generally configured to cover the opening of the railcar 110, and provide access to the interior of the railcar 110. In FIG. 1, the door 120 is illustrated in a closed configuration. In the open configuration, the door 120 is configured to slide to a side of the opening of the railcar to allow loading and unloading the railcar 110.

In the illustrated embodiment, a single-side door 120 is shown, meaning that the door 120 can slide to one side of the opening. In other embodiments, the door 120 may be a double-sided door, meaning that when opening the door 120, the left side of the door 120 is slid to the left side, and the right side of the door 120 is slid to the right side of the opening. In the illustrated embodiment, the door 120 comprises a latching system 130, a locking system 140, a sealing system 150, an interface system 160, a sliding system 170, locking rods 180, and cams 190. In other embodiments, the door 120 may not have all of the components listed and/or may have other elements instead of, or in addition to, those listed above.

Latching system 130 is generally configured to plug the door 120 to the railcar 110 or unplug the door 120 from the railcar 110. The latching system 130 may be installed at any suitable location on the door 120. For example, the latching system 130 may be installed on the door 120 at a height that can be operated by an operator. In one embodiment, latching system 130 comprises one or more gears operably coupled with a lever 210. When opening the door 120, the lever 210 is rotated by applying a force (e.g., a pushing force, a pulling force) that causes the one or more gears to pivot around their centers or internal bearings, and causes the door 120 to plug or unplug (or latch or unlatch) from the railcar 110. Details of the latching system 130 and its operation are described in the corresponding description of FIG. 2.

Locking system 140 is generally configured to lock and unlock the door 120. In the illustrated embodiment, the locking system 140 is installed on the left side of the door 120. In other embodiments, the locking system 140 may be installed on either or both left and right sides of the door 120. The locking system 140 comprises a latch bar 320 (see FIG. 3) that at one end is attached to the door 120 and a latch hinge 330 (see FIG. 3) that is attached to the railcar 110. The door 120 can be locked when the latch bar 320 and latch hinge 330 (see FIG. 3) are aligned and engaged with each other. Details of the locking system 140 and its operation are described in the corresponding description of FIG. 3.

Sealing system 150 is generally configured to create sealing surfaces on or near the outboard side of the structure around the door 120 between the door 120 and the railcar 110. In other words, the sealing system 150 is configured to prevent air leakage between mating surfaces of the door 120 and the railcar 110. The sealing system 150 is installed on the door 120 such that it leaves more clearance 520 (see FIG. 5) to the interior space of the railcar 110 compared to current railcar door design technologies. In one embodiment, sealing system 150 comprises a plurality of sealing components 420 (see FIG. 4A-4C) that is attached to the interior surface of the door 120. The sealing components 420 of the sealing system 150 are arranged adjacent to the outboard side of the structure around the door 120 to provide more clearance to the interior space of the railcar 110. Details of the sealing system 150 and its operation are described in the corresponding description of FIG. 4A-5.

Interface system 160 is generally configured to interface with a forklift to open and close the door 120. In some embodiments, the interface system 160 may be configured to interface with any device that could be used to open and close the door 120 as would be appreciated by one of ordinary skill in the art. For example, the device may be a railcar door opener device and the like. One of the purposes of implementing the interface system 160 is to provide a configuration that interfaces with the forklift to avoid or minimize damaging the door 120 when the device (e.g., a forklift) pushes or pulls the door 120 to open or close the door 120. The interface system 160 may comprise pockets that are shaped (e.g., deep enough and wide enough) to accept a piece of a railcar opening device, for example, a blade of a forklift. Details of the interface system 160 and its operation are described in the corresponding description of FIG. 6.

Sliding system 170 is generally configured to slide the door 120 to close and open the opening of the railcar 110. During opening the door 120, using the sliding system 170, the door 120 is slid into a stored position on the side of the opening on rail guides. Similarly, during closing the door 120, the door 120 is slid into a stored position in front of the entrance of the railcar 110, blocking the entrance. The sliding system 170 may comprise one or more rollers on the bottom of the door 120 to slide the door 120. Details of the sliding system 170 and its operation are described in the corresponding description of FIG. 7A and 7B.

FIG. 2 illustrates a front view of an embodiment of the latching system 130. The latching system 130 may be mounted to the door 120 using any suitable technique including bolting, welding, and the like. The latching system 130 may be mounted to the door 120 at any suitable location. For example, the latching system 130 may be mounted at a height that is easily accessible to be operated by an operator. For example, the latching system 130 may comprise a mounting or backing plate that allows the latching system 130 to be bolted to the door 120.

The latching system 130 may comprise a lever 210 and two or more gears 220. In the illustrated embodiment, the latching system 130 comprises a lever 210, a first gear 220 a, and a second gear 220 b. The lever 210 is configured to allow an operator to rotate the lever 210 by pivoting the lever 210 clockwise or counter-clockwise (shown as rotation 230) to plug the door 120 to the railcar 110 or unplug the door 120 from the railcar 110. The lever 210 may be formed in any suitable shape that allows the operator to rotate the lever 210. For example, the lever 210 may be formed to have different widths along its length. In the illustrated embodiment, the lever 210 is formed to have narrow ends and a wider middle section.

In the illustrated embodiment, the lever 210 is coupled to the first gear 220 a at the center of the first gear 220 a. The lever 210 may be coupled to the first gear 220 a at any section of the lever 210 to generate a force (e.g., torque force) when rotating the lever 210. For example, the lever 210 may be coupled to the first gear 220 a at an offset section with respect to the middle of the lever 210.

The first gear 220 a comprises a first set of teeth on its outer edge. The first gear 220 a has a first radius 222 a that may correspond to the number of teeth of the first gear 220 a and/or the size of the first gear 220 a. The second gear 220 b comprises a second set of teeth on its outer edge. The second gear 220 b has a second radius 222 b that may correspond to the number of teeth of the second gear 220 b and/or the size of the second gear 220 b. The first gear 220 a is configured to engage with the second gear 220 b when the first set of teeth of the first gear 220 a are engaged with the second set of teeth of the second gear 220 b.

The lever 210 may be rotated a particular number of rotations to plug or unplug the door 120. This particular number of rotations is determined based at least on the ratio of the first radius 222 a of the first gear 220 a over the second radius 222 b of the second gear 220 b, i.e., a gear ratio. The ratio of the first radius 222 a over the second radius 222 b is determined such that the lever 210 is operable to turn when a force within a target force range is applied to turn the lever 210 the particular number of rotations.

In one embodiment, the ratio of the first radius 222 a over the second radius 222 b may be any suitable gear ratio as would be appreciated by one of ordinary skill in the art, such as a gear ratio between 1.1 to 8. In one embodiment, the particular number of rotation for the lever 210 may be a number as would be appreciated by one of ordinary skill in the art, such as any number between 0.5 to 3. For example, the ratio of the first radius 222 a over the second radius 222 b may be determined to minimize the force (e.g., torque force) applied to the lever 210 to plug and unplug the door 120. The lever 210 and gears 220 operably coupled with the locking rods 180 and cams 190 to plug and unplug the door 120.

Locking rods 180 are generally configured to provide support to the structure of the door 120 and to be used to move the door 120 inwards to plug the door 120 to the railcar 110 and outwards to unplug the door 120 from the railcar 110. Each locking rod 180 comprises two cams 190 at its ends, i.e., a first cam 190 at the top and a second cam 190 at the bottom end. The door 120 may comprise any suitable number of locking rods 180, such as one rod, two rods, etc. In the illustrated embodiment, the door 120 comprises two locking rods 180, one at the left and the other at the right side of the door 120. The locking rods 180 may be coupled to the door 120 at one or more places, for example, by welding, bolting, and the like.

Each cam 190 is configured to engage with a keeper 250 attached or mounted to the railcar 110. Each locking rod 180 is positioned such that its cams 190 (on the top and bottom ends) are substantially aligned and engaged with corresponding keepers 250 when the door 120 is closed. Each cam 190 comprises one or more hook portions that are configured to engage with a keeper 250. The hook portions are configured to hook underneath the lobe of the keeper and apply a force (e.g., a pulling force) to the lobe to couple the locking rod 180 to the corresponding keeper 250, thus, securing the door 120 in plugged configuration.

During plugging the door 120 to the railcar 110, the lever 210 is rotated in a first direction, e.g., clockwise. Rotating the lever 210 may cause the first gear 220 a to rotate in the first direction as well. Since the teeth of the first gear 220 a are engaged with the teeth of the second gear 220 b, rotation of the first gear 220 a in the first direction causes the second gear 220 b to rotate in a second direction, e.g., counter-clockwise.

The second gear 220 b is operably coupled or attached to the locking rods 180 by plates 260. When the second gear 220 b rotates, it causes the locking rods 180 to rotate around their vertical axis. This process causes the cams 190 of the locking rods 180 to rotate and engage their corresponding keepers 250 mounted on the railcar 110 adjacent to the cams 190. Thus, the door 120 moves inwards to the closed configuration and gets plugged to the railcar 110.

Likewise, during unplugging the door 120 from the railcar 110, the lever 210 is rotated in the second direction (e.g., in a counter-clockwise direction), which causes the gear 220 a to rotate in the second direction. This causes the second gear 220 b to rotate in the first direction (e.g., in a clockwise direction), which then causes the locking rods 180 to rotate around their vertical axes. As such, the cams 190 rotate around their vertical axis and disengage from their corresponding keepers 250. Thus, the door 120 moves outwards to the open configuration and gets unplugged from the railcar 110.

Locking backplate 240 is generally configured to secure the lever 210 at the default resting position of the lever 210. For example, when the door 120 is plugged, the lever 210 can be secured to the locking backplate 240 to prevent or minimize unintentional movements of the lever 210. The locking backplate 240 may be installed on the door 120 at any appropriate location to accommodate securing the lever 210. For example, the locking backplate 240 may comprise a plate to cover or be positioned over the lever 210 when one end of the lever 210 sits on the locking backplate 240. In one embodiment, the locking backplate 240 may be bolted to the door 120. In other embodiments, the locking backplate 240 may be coupled or integrated to the door 120 by any other suitable technique including bolting, welding, and the like.

FIG. 3A illustrates an isometric view of an embodiment of the locking system 140. FIG. 3B illustrates a top view of an embodiment of the locking system 140. In the illustrated embodiment, the locking system 140 comprises a latch bar 320 and a latch hinge 330. Latch bar 320 comprises a bar plate that from the left end is coupled to the railcar 110, and from the right end is configured to engage with the latch hinge 330. As such, the latch bar 320 and the latch hinge 330 are substantially aligned to engage with each other.

In the illustrated embodiment, the latch bar 320 is bolted to the railcar 110 at the left end. In other embodiments, the latch bar 320 may be coupled to the railcar 110 by any other suitable technique including welding, and the like. The latch bar 320 is formed to have a hook or loop-shaped component 340 at the right end. The loop-shaped component 340 is formed to engage with a latch hinge 330 when the door 120 is in the closed configuration.

Latch hinge 330 comprises a backplate 350 that is coupled (bolted or welded) to the door 120 and a loop-shaped component 360 that is coupled to the backplate 350 (bolted or welded). The loop-shaped component 360 of the latch hinge 330 is formed to engage with the loop-shaped component 340 of the latch bar 320. The latch hinge 330 is positioned on or coupled to the door 120 such that one end of the loop-shaped component 360 can fit inside the loop-shaped component 340. When the door 120 is plugged to the railcar 110, the door 120 can be locked by moving the latch bar 320 toward the latch hinge 330 and fitting one end of the loop-shaped component 360 inside the loop-shaped component 340. Once one end of the loop-shaped component 360 is placed inside the loop-shaped component 340, the loop-shaped component 340 can be secured by using a padlock and the like.

FIGS. 4A-4C illustrate different cross-sections of an embodiment of the sealing system 150 of the door 120. FIG. 4A illustrates a side view of a cross-section of the top of the door 120. FIG. 4B illustrates a top view of a cross-section of a side of the door 120. FIG. 4C illustrates a side view of a cross-section of the bottom of the door 120. In FIGS. 4A-4C, the door 120 is shown in the closed or plugged configuration. In the illustrated embodiment, the sealing system 150 comprises a plurality of sealing components 420. The sealing components 420 are used to create sealing surfaces on or near the outboard side of the structure around the door 120 between the door 120 and the railcar 110. A top portion sealing component 420 attached to the top portion of the door 120 is illustrated in FIG. 4A. A side portion sealing component 420 attached to the side portion of the door 120 is illustrated in FIG. 4B. A bottom portion sealing component 420 attached to the bottom portion of the door 120 is illustrated in FIG. 4C. The plurality of sealing components 420 is deposited or positioned inside or near a door post 410.

Door post 410 is generally a portion of the structure of the door 120 that surrounds the frame of the door 120. The sealing components 420 are attached to the interior surface of the door 120 such that they create a sealing surface along the path of the perimeter of the door 120.

Each of the plurality of sealing components 420 comprises a sealing gasket 440. The sealing gasket 440 may be in a form of a ring made of flexible material or an elastomeric ring that is attached to the door 120. The sealing gasket 440 allows creating a seal between mating surfaces with irregularities (i.e., between the door 120 and railcar 110), such as rough surfaces, bumpy surfaces, and the like. In one embodiment, the sealing gasket 440 may comprise a rubber body portion to create a seal between the door 120 and railcar 110. In other embodiments, the sealing gasket may comprise any suitable sealant material including paper, silicon, nitrite rubber, fiberglass, plastic polymer, and the like.

The sealing gasket 440 is configured to fill the space between the door 120 and the railcar 110 when the door 120 is in the plugged configuration. For example, when the door 120 is in the plugged configuration, the sealing gasket 440 is compressed, thus, creating a seal between the door 120 and railcar 110. In one embodiment, the sealing gasket 440 may be attached to the door 120 using adhesives, such as glue. In other embodiments, the sealing gasket 440 may be attached to the door 120 including using adhesive materials, bolting, and the like.

As illustrated in FIGS. 4A-4C, the sealing components 420 are compressed between the door 120 and the railcar 110 (see FIG. 1) to create a seal and fill the space between the door 120 and the railcar 110. In FIG. 4C, a bottom sill 430 of the door 120 is also illustrated. The bottom sill 430 is configured to meet the floor of the railcar 110 when the door 120 is in the plugged configuration. As such, the bottom sill 430 provides further stability and a seal to the structure of the door 120.

FIG. 5 illustrates a top view of a cross-section of a side of the door 120. In the illustrated embodiment, the door post 410 has a cross-section width 510. The sealing gasket 440 of the sealing component 420 is deposited inside the door 120 adjacent to the post 410 such that it creates extra clearance space 520 to avail more room for the interior of the railcar 110.

FIG. 6 illustrates an embodiment of the interface system 160. The interface system 160 may be installed at any suitable location on the door 120. For example, the interface system 160 may be installed at or close to a mid-height of the door 120 that would be easily accessible to interface with a forklift that would cause the least pressure to the door 120 during the opening and closing processes of the door 120. In the illustrated embodiment, the interface system 160 comprises two push pockets 610. In other embodiments, the interface system 160 may comprise any suitable number of push pockets 610. The push pocket 610 provides an opening space or “pocket” to interface with a device, such as a forklift, to push or pull the door 120. For example, each push pocket 610 may have any suitable shape, such as a pocket having a length, width, and depth from, 2, 2, and 2, to 20, 20, and 20 inches, respectively. The push pockets 610 may be placed on the door 120 at any suitable location. In the illustrated embodiment, two push pockets 610 are placed at either side of the door 120. Each push pocket 610 is shaped to accept a piece of a railcar opening device, such as a blade of a forklift. In certain embodiments, the push pocket 610 may form a receding portion that is shaped to accept a piece of the railcar opening device. The push pockets 610 may be formed or integrated into a bar plate 620. The bar plate 620 may be mounted on the door 120 by any suitable method, such as bolting, welding, and the like.

FIG. 7A illustrates a front view of an embodiment of the sliding system 170. The sliding system 170 comprises rollers 740 connected to the bottom of the door 120. The door 120 can move along the rail guide 730 using the rollers 740. For example, during opening and closing the door 120, the door 120 is slid along the rail guides 730. When the door 120 is opened, the door 120 is slid to a stored location on a side of the entrance to the railcar 110. Likewise, when the door 120 is closed, the door 120 is slid to a stored location in front of the entrance of the railcar 110.

FIG. 7A further illustrates an embodiment of a side sill portion 710 of the door 120. The side sill portion 710 is generally configured to create a bottom sealing surface above the floor of the structure of the railcar 110 when the door 120 is in the closed configuration. In the illustrated embodiment, the side sill portion 710 comprises a metal plate bracket 720. The metal plate bracket 720, from its top end, is coupled to the bottom of the door 120. The metal plate bracket 720, from its bottom end, is engaged with the rail guide 730. In the illustrated embodiment, the bottom end of the metal plate bracket 720 is formed to fit within an open space 770 provided by the rail guide 730. The configuration of the metal plate bracket 720 and the rail guide 730, the sliding system 170, and the side sill portion 710 increase the stability of the structure of the door 120, and reduce vibrations and movements of the door 120 when moving and sliding, and further reduce vibrations and movements of the door 120 when the railcar 110 is traveling.

As further illustrated in FIG. 7A, there is a marginal space between the bottom end of the metal plate bracket 720 and the edges of the opening of the rail guide 730. As such, there is little to no friction or resistance between the bottom end of the metal plate bracket 720 and the edges of the opening of the rail guide 730 as the door 120 moves along with the rail guide 730. When the door 120 is in the closed configuration, the metal plate bracket 720 creates a metal-to-metal seal 750 with a metal bracket 760 that is coupled to the railcar 110. Therefore, the side sill 710 provides another bottom sealing surface in addition to the bottom section sealing component 420 described in FIG. 4C.

In addition to providing sealing surfaces between the door 120 and the railcar 110, the side sill 710 is integrated with the door 120, such that the side sill 710 allows for installing the door 120 on modular railcars 110, containers, trailers, vans, and the like. In modular railcars 110, the top portion of the railcar 110 (e.g., the roof, doors, and walls) can be separated from the bottom portion of the railcar 110 (e.g., the floor), and be replaced with a new top portion. In some cases, the new top portion of the modular railcar 110 may not have an opening to accept the door 120. If the side sill 710 had a cut-out for the door 120, it would cause higher stress on the side sill 710 than necessary. Therefore, the side sill 710 is formed without a cut-out for the door 120 and is coupled to the door 120 such that the door 120 can be installed on modular railcars 120.

FIG. 7B illustrates a front view of the door 120 with the side sill 710 surrounding the door 120. The side sill 710 allows having a space between the door 120 and the body of the railcar 110 with a height 770. Thus, the side sill 710 is not incorporated in the opening to the interior of the railcar 110. Height 770 indicates that the side sill 710 is formed without a cut-out for the door 120 that allows the door 120 to be installed on modular railcars 110.

While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated into another system or certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.

To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants note that they do not intend any of the appended claims to invoke 35 U.S.C. § 112(f) as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim. 

1. A door assembly for a railcar, comprising: a sliding system operable to slide a door to at least one side of the railcar to provide an opening path to an entrance of the railcar when the door is opened, wherein the sliding system comprises one or more rollers used for sliding the door; and a latching system operable to: plug the door to the railcar such that the door moves inward toward the railcar when closing the door; and unplug the door from the railcar such that the door moves outward from the railcar when opening the door, wherein the latching system comprises: a first gear with a first radius; a second gear operably coupled with the first gear, having a second radius; a lever operably coupled with the first gear and the second gear, wherein: the lever is operable to turn a particular number of rotations in a first direction to plug the door to the railcar; the lever is operable to turn the particular number of rotations in a second direction to unplug the door from the railcar; and a ratio of the first radius over the second radius is determined such that the lever is operable to turn when a force within a target force range is applied to turn the lever the particular number of rotations.
 2. The door assembly of claim 1, further comprising a locking system operable to lock the door, wherein the locking system comprises: a latch bar plate with a first length mounted on the door at one end, wherein the latch bar plate comprises a first space positioned within the latch bar plate; and a latch hinge mounted on the door with the first length apart from the latch bar plate, wherein: the latch hinge comprises a loop-shaped component that fits into the first space; and when the loop-shaped component is positioned in the first space, the door will be locked.
 3. The door assembly of claim 1, further comprising a sealing system operable to seal the door to the railcar when the door is closed, wherein the sealing system comprises: a plurality of sealing components attached to the interior surface of the door, comprising: a top portion sealing component attached to a top interior surface of the door; a side portion sealing component attached to a side interior surface of the door; and a bottom portion sealing component attached to a bottom interior surface of the door.
 4. The door assembly of claim 3, wherein: each of the plurality of sealing components comprises a sealing gasket that is in form of a ring; and the sealing gasket is configured to fill the space between the door and the railcar when the door is in a plugged configuration.
 5. The door assembly of claim 1, further comprising a side sill operably coupled to a sealing system of the door, comprising a bracket plate that is configured to create a sealed region when the bracket plate makes contact with a sealing plate of the door.
 6. The door assembly of claim 1, further comprising a push pocket operable to interface with a device to open or close the door, wherein the push pocket comprises a pocket that is shaped to accept a piece of the device such that when the piece of the device is positioned inside the pocket, the device can push the door to open or close.
 7. The door assembly of claim 6, wherein: the device comprises a forklift; and the piece of the device comprises a blade of the forklift.
 8. The door assembly of claim 1, wherein the door assembly is configured to be installed on a modular railcar such that a top portion of the modular railcar can be removed from a bottom portion of the modular railcar.
 9. The door assembly of claim 8, wherein: the top portion of the modular railcar comprises a roof, the door, and walls of the modular railcar; and the bottom portion of the modular railcar comprises a floor of the modular railcar.
 10. The door assembly of claim 1, wherein a sealing height at a bottom of the door between the door and a floor of the railcar is adjustable based at least on one or more of a weight of a cargo carried by the railcar, a size of the door, a type of the railcar, and a size of the railcar.
 11. A railcar, comprising: a door; and a door assembly operably coupled with the door, comprising: a sliding system operable to slide the door to at least one side of the railcar to provide an opening path to an entrance of the railcar when the door is opened, wherein the sliding system comprises one or more rollers used for sliding the door; and a latching system operable to: plug the door to the railcar such that the door moves inward toward the railcar when closing the door; and unplug the door from the railcar such that the door moves outward from the railcar when opening the door, wherein the latching system comprises: a first gear with a first radius; a second gear operably coupled with the first gear, having a second radius; a lever operably coupled with the first gear and the second gear, wherein:  the lever is operable to turn a particular number of rotations in a first direction to plug the door to the railcar;  the lever is operable to turn the particular number of rotations in a second direction to unplug the door from the railcar; and  a ratio of the first radius over the second radius is determined such that the lever is operable to turn when a force within a target force range is applied to turn the lever the particular number of rotations.
 12. The railcar of claim 11, wherein the door assembly further comprises a locking system operable to lock the door, wherein the locking system comprises: a latch bar plate with a first length mounted on the door at one end, wherein the latch bar plate comprises a first space positioned within the latch bar plate; and a latch hinge mounted on the door with the first length apart from the latch bar plate, wherein: the latch hinge comprises a loop-shaped component that fits into the first space; and when the loop-shaped component is positioned in the first space, the door will be locked.
 13. The railcar of claim 11, wherein the door assembly further comprises a sealing system operable to seal the door to the railcar when the door is closed, wherein the sealing system comprises: a plurality of sealing components attached to the interior surface of the door, comprising: a top portion sealing component attached to a top interior surface of the door; a side portion sealing component attached to a side interior surface of the door; and a bottom portion sealing component attached to a bottom interior surface of the door.
 14. The railcar of claim 13, wherein: each of the plurality of sealing components comprises a sealing gasket that is in form of a ring; and the sealing gasket is configured to fill the space between the door and the railcar when the door is in a plugged configuration.
 15. The railcar of claim 11, wherein the door assembly further comprises a side sill operably coupled to a sealing system of the door, comprising a bracket plate that is configured to create a sealed region when the bracket plate makes contact with a sealing plate of the door.
 16. The railcar of claim 11, wherein the door assembly further comprises a push pocket operable to interface with a device to open or close the door, wherein the push pocket comprises a pocket that is shaped to accept a piece of the device such that when the piece of the device is positioned inside the pocket, the device can push the door to open or close.
 17. The railcar of claim 16, wherein: the device comprises a forklift; and the piece of the device comprises a blade of the forklift.
 18. The railcar of claim 11, wherein the door assembly is configured to be installed on a modular railcar such that a top portion of the modular railcar can be removed from a bottom portion of the modular railcar.
 19. The railcar of claim 18, wherein: the top portion of the modular railcar comprises a roof, the door, and walls of the modular railcar; and the bottom portion of the modular railcar comprises a floor of the modular railcar.
 20. The railcar of claim 11, wherein a sealing height at a bottom of the door between the door and a floor of the railcar is adjustable based at least on one or more of a weight of a cargo carried by the railcar, a size of the door, a type of the railcar, and a size of the railcar. 